Lock nut



Def. 18, 1947. E. R. ROBERTS'N 1 2.432,805

Filed Jan. 10, 1945 the nut and bolt are screwed together.

Patented Dec. 16, 1947 LOCK NUT Edward Roker Robertson,

St. Margarets-on- Thames, Twickenham, England, assignor to ``Oliver Edwin Simmonds, Ripley, Surrey, England Application January 10, 1945, Serial No. 572,188 In Great Britain February 14, 1944 4 Claims. 1

This invention relates to self-looking nuts and like internally screw-threaded members (hereinafter referred to as a nut) of the kind oomprising a body portion having a sorew-threaded bore, and a looking member seoured to the non-working end thereof against relative rotary and axial bodily movement, the looking member having a bolt-thread engaging portion which, before the nut is sorewed on to a oo-operating bolt, is vout of helical alignment with the thread of the body portion of the nut and which is brought into helical alignment With such thread on sorevving the nut on to the bolt, the resulting displacement of the bolt-thread engaging portion of the locking member causin'g the looking member to flex with the result that it is caused to exert on the bolt an axial force which urges adjaoent sides of the threads of the nut and bolt together.

Various forms of self-looking nuts of the kind speoified have heretofore been proposed wherein the looking member is formed separately from the body portion of the nut and is made of spring steel, phosphor bronze or other hard resilient material.

It has been found that, in some cases, particularly Where the oo-operating bolt is made of a non-ferrous material which is considerably softer than the metal of which the looking member is made, there is a danger that the looking member may cause Wear to or otherwise damage the thread of the bolt, and the present invention has for its principal object to provide a self-looking nut of the kind specified in which this danger can be obviated.

In aocordanoe With the present invention I provide a self-looking nut of the kind specified With an additional member that is resilient andL that oo-operates with the looking member to resist fiexure thereof, the additional resilient member being adapted to clear the bolt thread When In this manner, the looking member may be made of any desired material having little or no resilienoy, the required resilienoy being provided by the additional resilient member. For example, the lockingi member may be made of the same material as the body portion of the nut, the resilient member being made of spring steel -or other desireol resilient material.

It is preferred lthat both the looking member and the additional resilient member be made separately from the body portion of the nut and in the form of apertured discs, the resilient member being arranged externally of and seating on the looking member so as to support the looking 2 member over substantially its whole area. lt is preferred, moreover, that the looking member be seated on the non-working end of the body portion of the nut so that its point of fiexure extends externally of the said portion of the i nut, and that the looking and resilient members be seoured to the said body portion by means depending from the periphery of the resilient member.

It is not necessary that the looking member should be of such form that its point of flexure is a cirole and the outer periphery of the locking member may be of a form other than ciroular.

The invention will be further desorbed with reference to the accompanying drawing, in which Fig. 1 is a top plan view of one form of selflooking nut in aocordanoe with the invention;

Fig. 2 is a Vertical sectional view taken on the line 2-2 of Fig. 1;

Fi'g. 3 is a top plan view of another form of nut in aocordanoe With the invention, and

Fig. 4 is a Vertical sectional view taken on the line 4-4 of Fig. 3.

The nut shown in Figs. 1 and 2 oomprises a body portion l which has a screw-threaded bore 2A and at its non-working end a neck or tubular extension 3. The body portion l is shown as having the usual hexagonal configuration but it may be of any other desired oontour. Seated on the end of neck 3 is the looking member 4 which is in the form of a centrally holed disc that is of uniform thickness and that is internally threaded at 5 to the same pitch and size as the threads of bore 2. It is preferred that the looking member 4 be relatively thin and it may have a thickness substantially equal to or substantially less than the pitoh of the threads of bore 2.

The resilient member is shown as being in the form of an annular disc 6 that is h'eld seated on the looking member 4 so as to support the looking member over substantially its whole area. The hole 1 in the resilient member B has a dlameter slightly greater than the maximum diameter of the threads of bore 2 so that such member 6 olears the threads of a oo-operating bolt when the nut is sorewed thereon. The composite I looking means is secured to the body portion of the nut against axial bodily movement by means depending from the outer periphery of the resilient member 6, and in the nut illustrated such means is in the form of a conical fiange 8 which is `secured to the neck 3 by upsetting the neck into interlocking engagement with the fiange,.by

pitoh with the thread of'the body portion, 'for example, by dishing the oentralportions of-tho looking and resilient members afshown. at 9.: It

is preferred to provide the resilientmember withf.

stiffening ribs and such ribs are advantageously provided on the looking member also,, the` ribs formed on the looking member preferably being. indented into the body portion of the nut whereby it and the looking member are keyed together against relative rotary movement.

In the nut shown in the drawing, stifiening ribs ID, llare simultaneously formed on the resilient and looking members respectively prior to the threading operation, the ribs H being indented into the end of neok 3.

It will be understood that, when the nut is screwed on to a bolt, the thread of the looking member 4,, being out of pitch, with the thread of the body portion I, is displaced axially to bring the threads of the two parts into phase. This axial displacement of the thread of the looking member causes both the looking member and the resilient member 6 to flex about afulcrum oirole of relatively large radius. Member 6, being resilient, and bearing on the looking member between the fulorum cirole formed at the inner edge of the outer end of the neok 3 and the threaded edge 5 which enters between the threads of the nut, tends to urge the looking member back to its out-of-pitch position with the result that the looking member is caused to exert on the bolt a strong axial force which urges the load-carrying sides of the threads of the nut and bolt together, thus preventing unintentional slackening of the nut.

The bolt-engaging portion ofv the looking member may take forms other than a thread.

In the nut shown in Figs. 3 and 4 the body portion of the nut and the resilient member'are generally similar to those shown in Figs. l and 2 and like reference numerals are used to denote like parts. The looking member li-is unthreaded and comprises a fiat centrally-holed disc of uniform thickness. The diameter of hole 2| in disc 20 is less than the maximum diameter of the threads z displaoed and twisted in exactlythe same way-as the looking member. It will be understoodthat, when thisform of nut isscrewed on to a bolt, the part of' the looking member adjacent hole 2| enters between the bolt threads and is axially disrplaced and twisted helically into helioal alignment with the threads of bore 2. This results in a corresponding displacement and twisting of the resilient member 6 which thus causes Vthe looking member to exert on the bolt an axial force which urges the load-oarrying sides of the threadsof the nut andbolt together. In the nut illustrated, the resilient member 6. and the lockingpmember 4 20 are provided with three stiillng ribs iii, 23 respectively, the ribs on the looking member being indented into the end of neok 3, as in the nut shown in Figs. 1 and 2. The shape of the resilient member 6 may, if desired, be such that the resilient. member gives. different' loadingson different vcirzcumferential parts .of the .looking member 20, and the leading may vary inversely to the axial displacement given to the Various parts of the bolt-engaging portion of the looking member. Although, in most cases, it is preferred that the looking member be'secured to the body portion of the. nut'so that its point of flexure occurs externa-llyof the body portion of the nut, as in the two forms of nut'illustrated, the composite lockinf;V meansmay, bel secured to the body portion of thenut. in other ways than that shown such that the looking member cannot move bodily in an axial'. direction and that the resilient member cooperates with the looking member to impart resiliency thereto.

The body portion of the improved nut may be formed from bar stock of hexagonal or other desired configuration or from sheot metal stock. The looking means may, moreover, comprise a plurality of looking members or a plurality of co- Operating resilient members, or both. If desired, the looking member may be formed of resilient material in which case the additional resilient member provides a looking means of enhanced resiliency.

I olaim:

1. A look nutcomprising a body portion having a screw-threaded bore, a looking member secured to the body portion against relative axial bodily movement and having a portion which is out of helioal alignment with the thread of Ithe bore of said body portion and which is adapted to, and is so positionedl asto enter between the threads of a oooperating bolt onto which the nut may be threaded, 'said body portion having a fulorum edge between its outer periphery and the threaded bore, a part of said looking member which is radially outward from the portion thereof which enters between the threads of a oooperating bolt bearing on said fulorum edge, and a resilient member seoured, to the bodyportion and exerting a force on said looking member between said fulorum edge and the portion of said looking member which enters between the thread of a oooperating bolt to resist flexure of said looking memberv about said fulorum edge,.the respective parts being so constructed and arranged that whenA the nut is screwed onto a oooperating bolt the portion of the looking member which enters between the threads of the bolt'is brought into helioal alignment with the threads of the bolt. and the body port-ion of theinut and. the looking member thereby flexeol, against pressure exerted thereon by said resilient member.

2. A looknut as set forth in olaim 1 in which the fulorum edge is 'of arcuate shape and substantially concentrio 'with the threaded bore of the body portion,

3. A lock. nut as set forth in olaim l in which the fulorum edge is. circularl and substantially conoentric` withthe. threadedbore of the body portion and in which the looking member is an apertured disc.

4. A lock nut; as set vforth in olaim 1 in which the lockingmember alsois secured to the body portion against relative rotary movement.

EDW'ARD ROKERl ROBERTSON.

(References on following page) Number REFERENCES CITED 2 221460 The following references are of record in the 2,391,989 file of this patent:

UNITED STATES PA'I'ENI'S 5 Number Name Date Number 1,550,282 Rennerfelt Aug. 18, 1925 538,497 1,791,017 Sundh Feb. 3, 1931 545,828 1,729,013 Rennerfelt Sept. 24, 1929 10 558,414

Name Date Crowley Nov. 19, 1940 Luce Jan. 1, 1946 FQREIGN PATENTS Country Date Great Britain 1 Aug. 6, .1941 Great Britain June 15, 1942 Great Britain Jan. 4, 1944 

